Boston, Massachusetts: Growth Constrained by State Charter Cap

As detailed above, many states have caps on either the number of charter schools that can exist or the number of students who can attend charter schools.

The city of Boston, Massachusetts has one of the highest performing charter sectors in the country, yet it also has one of the nation’s most restrictive charter caps. It offers a prime example of the challenge that restrictive charter school caps pose to the growth of high-quality charter schools.


Massachusetts passed its original charter law and cap under the Education Reform Act of 1993.1 The original cap was strict; no more than 25 charter schools could operate statewide, with no more than five allowed in Boston.2 Legislation passed in 1997 raised the cap to 50 schools statewide and created a new kind of semi-autonomous, in-district charter school called Horace Mann charters. In 2000, the cap was raised again to allow up to 120 schools (including a maximum of 72 Commonwealth charters and 48 Horace Mann charter schools). Under the 2000 legislation, no district could spend more than 9 percent of its total net spending on charter school tuition payments.3

In 2010, the legislature passed new legislation that raised the cap on charter schools in the lowest-performing 10 percent of districts statewide. Between 2011 and 2017, these districts can increase from 9 percent to eighteen percent the total tuition payments made to charter schools. Any new charter schools created above the previous cap are reserved for the replication of high-performing schools, and they do not count toward the statewide cap of 72 commonwealth charter schools.1 This change, an example of a “smart cap,” suggests an important shift in considering the quality — not just quantity — of charter schools in determining growth.

Despite the slight easing of the cap in 2010, charter school growth is severely constrained in the city. Commonwealth charter school enrollment in Boston spiked in the year following this legislation, increasing from 5,202 students in 2010–11 to 6,497 students in 2011–12 to 7,956 students in 2012–13. (Prior to the 2010–11 school year, enrollment was nearly stagnant, increasing by no more than 200 students each year).5 As of 2013–14, 25 charter schools served nearly 8,000 students.6 However, there were also approximately 27,000 names on charter school waitlists across the city, suggesting that Boston’s supply of charter schools is still far below their demand.7

Charter School Performance

As noted above, Boston is home to possibly the highest-performing charter sector in the country. A 2013 report by the Stanford University-based CREDO research institute found that 83 percent of Boston charters outperformed comparable district schools and 17 percent performed similarly. No Boston charter school underperformed relative to comparable district schools.8 Most notably, Boston’s charter schools produce large positive results for low-income black and Hispanic children. These students acquire more than a year’s worth of additional learning in both math and reading every year compared to similar students in Boston Public Schools (BPS).6

Figure 12. Additional Months of Learning in Boston Charter Schools Compared to District Schools

Chart by Visualizer

Source: Center for Research on Education Outcomes10

Attending a charter school in Boston has large positive effects on high school outcomes as well: Charter school attendance significantly increases the likelihood that applicants meet graduation competency standards and qualify for an Adams Scholarship11; the likelihood that a student will take an AP test and earn a passing score; and the likelihood that a student will apply to a four-year college. Boston’s charter school students’ average math SAT scores are statistically significantly higher than their BPS peers’ scores.12

Although the state has made recent changes to allow for the growth of high-performing charter schools, the supply of charter schools remains insufficient to ensure that all families who wish to enroll in a charter school are able to do so. Charter enrollment is expected to increase by approximately 3,000 students by 2014–15,13 at which point the new cap will be reached and further growth will be halted altogether. The Massachusetts Senate recently failed to pass a bill that would have increased this cap and allowed for further expansion of the charter sector.14

Although charter caps can encourage authorizers to be more discerning about which schools they approve and more vigilant in closing low-performing schools, individual states must ensure that their existing caps do not severely limit the growth of the sector, in particular the growth of high-performing schools and networks.

  1.  “Measuring Up: Massachusetts,” National Alliance for Public Charter Schools, accessed February 9, 2015,
  2. “Act 71 of 1993 Legislative Session,” State Library of Massachusetts (1993): 215, accessed February 9, 2015,
  3. “Charter schools in Massachusetts,” Ballotpedia, accessed February 9, 2015,
  4.  “Measuring Up: Massachusetts,” National Alliance for Public Charter Schools, accessed February 9, 2015,
  5. “Total Number of Students: Massachusetts,” National Alliance for Public Charter Schools, accessed February 9, 2015,
  6. Ibid.
  7. James Vaznis, “Charter school demand in Mass. Disputed,” The Boston Globe, April 8, 2013, accessed February 9, 2015,
  8. “Charter School Performance in Massachusetts,” Center for Research on Education Outcomes (2013): 37, accessed February 19, 2015,
  9. Ibid.
  10. “Charter School Performance in Massachusetts,” Center for Research on Education Outcomes (2013): 37, accessed February 19, 2015,
  11. Students can earn an Adams Scholarship that provides a tuition waiver for up to eight semesters of undergraduate education at a state college or university. For the classes of 2015 and earlier, eligibility requirements include: scores of advanced and proficient on grade 10 MCAS ELA and math (at least one score must be advanced); and combined scores on MCAS ELA and math that place them in the top 25 percent of students in the graduating class in their district. Beginning with the class of 2016, students must score advanced on one of ELA, math, or STE state tests; score proficient or higher on the remaining two; and have combined scores that place them in the top 25 percent of students graduating from their district (
  12. Joshua Angrist, Sarah Cohodes, Susan Dynarski, Parag Pathak, and Christopher Walters, “Stand and Deliver: Effects of Boston’s Charter High Schools on College Preparation, Entry, and Choice,” The National Bureau of Economic Research (2013): 2, accessed February 9, 2015,
  13. “Charter Seat Growth Should Drive BPS Reform,” Boston Municipal Research Bureau (2013), accessed February 19, 2015,
  14. Claire McNeill, “Mass. Senate rejects bill to raise charter school limit,” The Boston Globe, July 16, 2014, accessed February 9, 2015,
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